ch. ix.] 18311844. 175 



answer. He has said in the Autobiography (p. 39) that 

 certain facts observed by him in South America seemed to be 

 explicable only on the " supposition that species gradually 

 become modified." He goes on to say that the subject 

 " haunted him " ; and I think it is especially worthy of note 

 that this " haunting " this unsatisfied dwelling on the sub- 

 ject was connected with the desire to explain lioiv species 

 can be modified. It was characteristic of him to feel, as he 

 did, that it was " almost useless " to endeavour to prove the 

 general truth of evolution, unless the cause of change could 

 be discovered. I think that throughout his life the ques- 

 tions 1 and 2 were intimately perhaps unduly so con- 

 nected in his mind. It will be shown, however, that after 

 the publication of the Origin, when his views were being 

 weighed in the balance of scientific opinion, it was to the 

 acceptance of Evolution, not of Natural Selection, that he 

 attached importance. 



An interesting letter (Feb. 24, 1877) to Dr. Otto Zacha- 

 rias,* gives the same impression as the Autobiography : 



" When I was on board the Beagle I believed in the per- 

 manence of species, but as far as I can remember, vague 

 doubts occasionally flitted across my mind. On my return 

 home in the autumn of 1836, I immediately began to pre- 

 pare my Journal for publication, and then saw how many 

 facts indicated the common descent of species, so that in 

 July, 1837, I opened a note-book to record any facts which 

 might bear on the question. But I did not become con- 

 vinced that species were mutable until, I think, two or three 

 years had elapsed." 



Two years bring us to 1839, at which date the idea of 

 natural selection had already occurred to him a fact which 

 agrees with what has been said above. How far the idea 

 that evolution is conceivable came to him from earlier writers 

 it is not possible to say. He has recorded in the Autobiog- 

 raphy (p. 38) the " silent astonishment with which, about 

 the year 1825, he heard Grant expound the Lamarckian 

 philosophy." He goes on : 



" I had previously read the Zoonomia of my grandfather, 

 in which similar views are maintained, but without produc- 

 ing any effect on me. Nevertheless, it is probable that the 

 hearing rather early in life such views maintained and 



* This letter was unaccountably overlooked in preparing the Life and 

 Letters for publication. 



